Our invention relates to a method of operating a Claus-plant.
A process or method of operating a Claus-plant is known, in which an H.sub.2 S-containing input or reactant gas is first subjected to a partial combustion and after that is further reacted in a two or multistage Claus-reactor.
On performing the so-called Claus process the H.sub.2 S-containing reactant gas is first subjected to a partial combustion in a combustion furnace under such conditions that only a third of the hydrogen sulfide contained in the reactant gas is burned according to the following chemical reaction (I): EQU H.sub.2 S+1.5 O.sub.2 .fwdarw.SO.sub.2 +H.sub.2 (i)
In the combustion furnace a special catalytic layer can be installed, which acts to destroy the nitrogen compounds found in the reactant gas.
Subsequently the hot gas is cooled in a waste-heat boiler and after that fed into a two or multistage Claus reactor, in which the further reaction of the gas occurs in the presence of a catalyst according to the following chemical reaction (II): EQU 2 H.sub.2 S+SO.sub.2 .fwdarw.3 S+2 H.sub.2 O (II)
In the usual Claus-plant the combustion furnace with waste-heat boiler for partial combustion of reactant gas, the Claus reactor with associated devices and the sulfur precipitator are connected in series. The dimensions of this plant thus depend on the expected H.sub.2 S-content of the starting gas and the normal starting gas flow rate to be processed so that the capacity of the sulfur production in the plant is as a whole limited. Variations of the predetermined production capacity are possible only in a narrow limited range. In so far as increasing amounts of H.sub.2 S in the starting gas and starting gas flow rates were factored into the art, one attempted to solve these problems up to now by building two-or multistage Claus-plants. That means however an increased expense in plant operating and building costs, since in this case all plant units of the whole plant must be present as dual or multiple components and moreover in case of reduced sulfur production the unused plant components must be maintained in a heated condition, since during sudden increases of the required production capacity they must be operated continuously.